The present invention is principally concerned with the removal and/or replacement of conveyor idlers (or rollers) from a conveyor system. An idler is typically a cylindrical shaped component that rotates on a fixed central shaft, the central shaft being mounted on a frame structure. In order to minimize friction, an idler would rotate on the central shaft by way of bearings. In practice, a frame structure would support and mount a number of idlers. For example, a frame structure may include three carry (or top) idlers, which support the conveyor belt on its forward path, and one or more return (or bottom) idlers underneath the carry idlers which support the conveyor belt on its return path. A typical conveyor system would have frame structures positioned along the length of the conveyor at intervals of between 1.5 m to 3 m.
Idlers have a limited life due to two main fail conditions, the first being bearing failure by way of collapsing or seizing and the second being wear on the shell of the idler producing holes in the idler shell walls. Continued use of a failed idler can prove hazardous to the conveyor belt itself. In the case of a seized bearing, the belt would be moving over a stationary idler producing friction and resulting in local heating to the belt. This condition has been known to cause ignition of the conveyor belt and/or the material being carried on the belt.
To avoid such problems, a failed idler needs to be removed and replaced. To replace an idler, the conveyor belt firstly needs to be stopped and electrically isolated. The belt is required to be physically lifted to remove downward pressure on the idler to allow the idler to be accessed and removed from its frame. It will be appreciated that the need to stop the conveyor causes significant interruptions to production and adds costs for industrial users. The process of lifting the belt requires the use of lifting equipment. Furthermore, lifting the belt adds tension to the belt which creates a hazardous working environment for personnel accessing the idlers. A weakened belt may snap under increased tension and cause injury to personnel.
Accordingly, it is an object of the present invention to provide an improved process and means for removing and replacing conveyor idlers which minimises or avoids interruptions to the running of the conveyor, and which does not require the lifting of the conveyor belt.